An integrated circuit (“IC”) die may be assembled into an IC package by physically and electrically coupling it to a substrate made of organic or ceramic material. One or more IC packages may be physically and electrically coupled to a printed circuit board (“PCB”) to form an “electronic assembly”. The “electronic assembly” may be part of an “electronic system”. An “electronic system” is broadly defined herein as any product comprising an “electronic assembly”. Examples of electronic systems include computers (e.g., server, router, desktop, laptop, hand-held, Web appliance, etc.), wireless communications devices (e.g., cellular phone, cordless phone, pager, etc.), computer-related peripherals (e.g., printer, scanner, monitor, etc.), entertainment devices (e.g., television, radio, stereo, tape and compact disc players, video cassette recorder, camcorder, digital camera, MP3 (Motion Picture Experts Group, Audio Layer 3) player, etc.), and the like.
An IC package may comprise one or more IC dice. At least one surface of a die may comprise a number of pads or contacts to couple the die functionally to another element, such as an IC substrate. An IC substrate may comprise a number of layers. Some layers may comprise organic or ceramic dielectric material. Some layers may comprise conductors, such as traces, ground planes, and vias. An IC substrate may include an electronic component mounted on a surface of the substrate. The electronic component may be functionally connected to other elements of an electronic system through a hierarchy of conductors that include the substrate traces, ground planes, and vias. The conductors may carry signals that are transmitted among the electronic components, such as IC's, of the system. An IC substrate may have a relatively large number of input/output (“I/O”) terminals (also called “lands”), as well as a large number of power and ground terminals or lands, on a surface of the IC substrate.
In the field of electronics there is competitive pressure among manufacturers to drive the performance of their equipment up while driving down production costs and maintaining acceptable yield and reliability. This is particularly true regarding the packaging of dice on substrates, where each new generation of packaging must provide increased performance, particularly in terms of higher clock frequencies, while generally being smaller or more compact in size.
The I/O performance of an IC package that comprises two or more IC dice is affected by the length of interconnect lines used to couple the terminals on each die and the substrate. As the number of terminals that must be connected increases on each die, the lengths of the interconnects may need to be increased for proper routing. As the lengths of the interconnect lines are increased, there is greater likelihood that I/O performance will be degraded by interconnect parasitics, increased resistance, and the like.
For the reasons stated above, and for other reasons stated below that will become apparent to those skilled in the art upon reading and understanding this disclosure, there is a significant need in the art for apparatus and methods for packaging two or more dice on a substrate that optimize I/O performance and minimize production costs associated with multiple-die IC packages.